The relationship between riparian areas and biological diversity

1
The relationship between riparian areas and
biological diversity

• A comparison of streams in eastern Colorado and
  southwestern Virginia

By Ann Widmer 12-9-03
2
EPAs need for monitoring

• EPA Administrator William Reilly (1989)
• Good News Based on my years in the
  environmental movement, I think the Agency does
  an exemplary job of protecting the nations
  public health and quality of the environment.
  Bad news I cant prove it.
• http//www.epa.gov/emap.html

3
(environmental monitoring and assessment program)

• Key components
• statistical design
• wide-scale application across the country
• use of biological indicators

4
What is an indicator?

• An instrument for monitoring the operation or
  condition of a physical system
• Websters II New Riverside University Dictionary

5
EMAP Measurements

• Fish assemblage
• Benthic macroinvertebrates
• Periphyton
• Water quality
• Habitat parameters
• Substrates
• Embeddedness
• Riparian vegetation

Plecoptera (stonefly)
Periphyton on river rocks
6
Do indicators work?(Are they a good measure of
ecological health?)
7
2 healthy aquatic systems
Completely different stream character.
8
My project

• EMAP sampling in Colorado
• Concerns
• Qualitative data
• Comparison of trends to those in southwest
  Virginia
• Development of indicies
• Intensively studied area

9
Trends in southwest Virginia

• 1. As riparian vegetation is decreased, fish and
  mussel species diversity is decreased
• Diamond, J.M., and V.B. Serveiss. 2001.
  Identifying sources of stress to native aquatic
  fauna using a watershed ecological risk
  assessment framework. Environmental Science
  Technology 35 4711-4718.

10
Trends in southwest Virginia

• 2. As riparian vegetation is decreased, benthic
  macroinvertebrate density is decreased. Effect
  more pronounced very locally (within 200 meters)
• Sponseller, R.A., E.F. Benfield, and H.M. Valett.
  2001. Relationships between land use, spatial
  scale, and stream macroinvertebrate communities.
  Freshwater Biology 46 1409-1424.

11
Colorado streams(variation with elevation)
Above timberline
12
Colorado streams(variation with elevation)
Forested mountain
13
Colorado streams(variation with elevation)
Urban Front Range
14
Colorado streams(variation with elevation)
Plains
15
Contrary trends?
Above timberline Forested mountain Urban Front Range Plains
Riparian vegetation (relative to stream size) 1 4 3 2
Macro- invertebrate diversity 1 4 3 2
Fish species diversity 1 2 3 4
16
Additional considerations

• Scale
• Virginia studies were in a small watershed
• Colorado study encompasses half a state compare
  within similar conditions
• Sedimentation
• Land use and fish stocking
• Water quality

17
Comparison of similar streams

• Bear Creek, CO
• Boulder Creek, CO
• Clear Creek, CO
• Found the highest fish species diversity and
  density in the Bear Creek, the one with the most
  riparian vegetation

18
Recommendations to the EPA

• Indicators should not be used to compare health
  of dissimilar streams
• Different states big difference in riparian
  size
• Different elevation
• Different stream order
• Indicators most useful when comparing the same
  site over time environmental monitoring